Pneumatic governor for internal combustion engines



May 10, 1938. E. HOL ZBAUR 2,117,247

PNEUMATIC GOVERNOR FOR INTERNAL COMBUSTION ENGINES Filed Oct. 26, 1936 Patented May 10, 1938 PATENT OFFICE PNEIMATIO GOVERNOR, FOR, INTERNAL COMBUSTION ENGINES Eugen Holzbaur, Stuttgart, Germany, assignor to Robert Bosch Gesellschaft mit beschriinkter Haftung Application October 26, 1936, Serial No. 107,717 In Germany November 21, 1935 '1 Claims. 123-139) The present invention relates to a stopping device for internal combustion engines of the type which comes into operation on commencement of unintentional reverse of an engine operating with injection of liquid fuel, and wherein an injection-amount governor responsive to the vacuum in the induction pipe of the engine, reduces the amount of injected fuel when the vacuum increases by its movable governing member indirectly or directly displacing the control member for the fuel amount, and increases the injected fuel on a decrease in the vacuum by moving the fuel-amount adjusting member in the opposite direction assisted by a return spring or 16 the like.

In internal combustion engines the pneumatic governor of which governs the amount of fuel injected in dependence on the pressure in the airinduction pipe of the engine, the engine may start 20 to run in the reverse direction, especially in vehicle engines, whereby the flow in the induction pipe reverses, and particularly when the throttlevalve is closed produces an excess pressure in the governing chamber of the pneumatic governor connected to the induction pipe. In pneumatic fuel injection amount governors whose movable governing member is not fastened to the controlling rod but only contacts with it and pushes it in front of itself to reduce the fuel amount 30 when the vacuum increases, this excess pressure can separate the movable governing m'ember (piston or diaphragm) from the controlling rod and move it into the end-position corresponding to full load, this being even assisted by the return- 5 ing force. In doing so, it leaves the way free for the adjustment of the controlling rod to full load,

so that the controlling rod in striving to follow the movable governing member is now' also adjusted, for example by a spring, in the direction 40 of full load, and the engine might run uncontrolled i i the driver does not pull the controlling rod to stop in time.

In order to obtain an automatic stopping of the engine directly after the undesired starting to run 45 in reverse, according to the invention the operative connection of the fuel-amount adjusting member with the movable governing member is arranged within the governing chamber exposed to the fluctuating governing pressure, and so con- 50 structed, that the excess pressure that occurs in the governing chamber on a reversal of the direction of rotation of the engine separates the fuel amount governing member of the injection pump from the movable governing member while over- 55 coming the returning force, and moves it into that position in which the pump no longer pumps sufllcient fuel to keep the engine running idly.

Various examples of construction are shown in the accompanying drawing, in which:-

Fig. 1 shows an arrangement of a pneumatic 5 governor having a piston covered by a bellows on the controlling rod, and

Fig. 2shows an example in which the controlling rod carries a piston running in a guide.

In an injection pump of known construction 10 the casing is marked I, the cam-shaft 2, and the pump pistons, only one of which is shown, 3. Each of the pump pistons 3 is rotatable about its axis by means of the toothed control rod 4, whereby the position of an oblique controlling edge on the piston is altered relative to the return flow opening, and the amount of fuel sprayed by each piston into the internal combustion engine can be regulated. The control rod 4 contacts with the governor member or piston 5 of a pneumatic vacuum governor 6 built on the easing l, in the chambers I and 8 of which governor different pressures prevail during working. One end of the governor chamber I is formed by a part of the casing I of the injection pump, the said chamber 1 being connected by a pipe 9 with the induction pipe Ill of the engine so that the vacuum present in the induction pipe can extend* to the governor chamber 'L The chamber 8 is' in communication with the atmospheric air pres- 0 sure, which moves the piston 5 to the left against the action of a spring II when the vacuum increases.

At the end of the controlling rod 4 projecting into the governor chamber 1 an auxiliary piston I2 is arranged according to the invention, which piston, by means of a spring l3 provided between it and the casing I, is held with one of its faces in contact with a pressure pin 5a of the main governing piston 5. The other face of the auxil- 40 iary piston I2 is covered by bellows l4 so that said face is not directly exposed to the pressure existing in the governor chamber. The carrier SD for the main governor piston 5 is guided within an externally threaded bush l5 arranged in the casing 6 of thepneumatic governor, and this bush serves as an adjustable stop for the piston and for adjusting the maximum delivery amount of the pump. The stopping lever 16 acts on the end of the piston carrier 5b.

The mode of working of the apparatus is as follows:

During ordinary running of the engine, the induction air flowing in the direction of the arrow A produces a vacuum in the pipe 9 and in the governor chamber I, which draws the main piston 5 to the left against the action of the spring The pressure pin 5a of the main piston at the same time pushes the control rod I also to the left and compresses the weak spring It so as to cause a reduction of the injection amount. As soon however as the engine for any reason'starts to run in reverse and the cylinder contents discharge into the induction pipe ID in the direction of the arrow B (Fig. 2), an excess pressure occurs in the pipe 9 and in the chamber 1, which tends to drive apart the two pistons 5 and ii in opposite directions. cess pressure occurs moves the piston to the right into the end-position which during normal working would correspond to the adjustment of the pump to the full injection amount. As however the control rod 4 is not rigidly connected with the main piston, but itself carries an auxiliary piston on whose face the excess pressure can act, the control rod moves in an opposite direction to the main piston when an excess pressure occurs in the governor chamber, and so adjusts the pump that no fuel delivery is possible whereby the engine is automatically stopped. The spring l3 in the bellows I4 is in this case compressed by the auxiliary piston. Before a sufficiently high vacuum again occurs in the governor chamber in passing over to normal working; the spring l3 brings the controlling rod again into contact with the pressure pin 5a of the main governing piston 5, so that the correct adjustment between'the controlling rod and auxiliary piston, on the one hand, and the main governor piston, on the other hand, is restored.

The example of construction in Fig. 2 shows a governor member 5 made as a diaphragm; the diaphragm is stiffened by plates 50 by which the pressure pin to" is held. The auxiliary piston I2 is arranged so as to be movable in a guidesleeve l'l. When the vacuum increases the pressure pin pushes the auxiliary piston l2 in the guide-sleeve i1 towards the left i. e. in the reduced fuel direction, while the spring I3 is compressed. On an excess pressure occurring in the governor chamber, this can only act on one face of the auxiliary piston,'and move this piston in the stop direction as the guide-sleeve covers the rear side of the auxiliary piston. The space enclosed by the auxiliary piston and the guide-sleeve or the bellows has an air hole I8. In the cover of the casing 6' is a stop-screw IQ for the member 5', which limits the maximum delivery amount of the pump.

I declare that what I claim is:

1. Fuel injection control means for internal combustion engines comprising in combination a governor member responsive to the vacuum in the induction pipe of the engine, a member for adjusting the amount of fuel supply to the engine under the control of said governor member, whereby the fuel injected is reduced with increase of the vacuum in the induction pipe of the engine and vice versa, a governor chamber in communication with the induction pipe of the engine and a connection between the adjusting member and the governor member within said governor chamber which on the application of excess pressure in the governor chamber on a reversal of direction in rotation of the engine, causes displacement of the adjusting member independently of the governor member to a position in which no fuel is supplied to the engine.

2. Fuel injection control means for internal combustion engines comprising in combination a The spring II when the exgovernor member responsive to the vacuum in the induction pipe of the engine, a member for adjusting the amount of fuel supply to the engine under'the control of said governor member, a governor chamber in communication with the induction pipe of the engine and a. connection between the adjusting member and the governor member within said governor chamber for their displacement in unison whereby the fuel injected is reduced with increase of the vacuum in the induction pipe of the engine and vice versa, said connection including a pressure responsive face provided on said adjusting member in the governor chamber whereby when said face is subjected to the vacuum in said governor chamber, connection between said adjusting member and the governor member occurs in said chamber, which connection on the application of excess pressure in the governor chamber due to a reversal of direction in rotation of the engine is destroyed automatically to enable the adjusting member to be displaced independently of the governor member to a position in which no fuel is supplied to the engine.

3. Fuel injection control means for internal combustion engines comprising in combination, a governor chamber in communication with the induction pipe of the engine, a displaceable governor member responsive to the vacuum in the induction pipe of the engine, a member for adjusting the amount of fuel supply to the engine and displaceable with said governor member when a vacuum exists in said governor chamber, whereby the fuel injected is reduced with increase of and vice versa, and a resiliently loaded element on the adjusting member, the resiliently loaded element being provided with a pressure responsive face in the governor chamber, whereby when a vacuum exists in said chamber, connection between the adjusting member and said governor member is maintained, and when an excess pressure exists in said chamber, due to a reversal of direction in rotation of the engine, the connection between the adjusting member and the governor member within the governor chamber is destroyed, to enable the adjusting member to be displaced independently of the governor member by said pressure in the governor chamber to a position in which no fuel is supplied to the engine.

4. Fuel injection control means for internal combustion engines comprising a governor chamber in communication with the induction pipe of the engine, a governor member in said chamber displaceable responsive to the degree of vacuum therein, resilient means resisting displacement of said governor member with increase of vacuum. a resiliently loaded member located within said governor chamber for adjusting the amount of fuel supplied to the engine, pressure-responsive means within said governor chamber between said governor member and said fuel supply adjusting member which is displaced with said governor member on variation in said vacuum so long as a vacuum exists in said governor chamber but permits independent displacement of said adjusting member on reversal of direction of rotation of the engine when excess pressure prevails in said governor chamber, said adjusting member and said governor member being displaceable in opposite directions on application of pressure to enable the adjusting member to take up a position consistent with prevention of fuel supply to the engine.

5. Fuel injection control means as set out in claim 4 in which the pressure-responsive means comprises a bellows mounted in said governor chamber.

6. Fuel-injection control means as set out in claim 4 in which the pressure responsive means comprises a piston, and aguide sleeve having one end opening into said governor chamber and the other end closed to said chamber for supporting under the control of said governor member, whereby the fuel injected is reduced with increase of the vacuum in the induction pipe of the engine and vice versa, a governor chamber in communication with the induction pipe of the engine, and a loose connection between the adjusting memher and the governor member within said governor chamber, said connection including pressure-actuated means which on the application of excess pressure in the governor-chamber on a reversal of direction in rotation of the engine causes displacement of the adjusting member independently of the governor member toward, a position in which no fuel is supplied to the engine.

' EUGEN HOLZBAUR. 

